System for transporting containers, which is especially suitable for use in a plant for the production of paints, varnishes and the like

ABSTRACT

A system for transporting containers, which is especially suitable for use in a plant for the production of paints, varnishes and the like, comprises a longitudinally extending bearing structure for containers. The structure in turn comprises a first, fixed, prtion defining one or more fixed bearing surfaces, and a second, movable, portion defining one or more movable bearing surfaces. Handling means are coupled operatively to the movable portion in order, in use, to bring about coordinated movements of lifting/lowering and longitudinal advance/return of the movable portion relative to the fixed portion.

[0001] The present invention relates to the field of industrial plantsfor the production of paints, varnishes, enamels, inks and the like, andin particular to a system for handling containers in those plants.

[0002] Known types of industrial plant for the production of paints andvarnishes usually comprise lines for handling the paint containers whichare carried in sequence to processing stations including, for example,stations for filling, for metering and delivering dyes, for mixing, forweighing and checking, and also for packing, storing and/or despatching.

[0003] An example of an industrial plant of the type indicated above isdescribed in the document EP-A-0 427 497 which illustrates aconventional container-handling system which comprises tracks havingidle and/or motor-driven rollers which transport the containers alongpredetermined paths. Other transport and handling systems normally usedalso in other technological fields involve the use of endless andmotor-driven conveyor belts, the upper face of which supports thecontainers which are to be transported from one station of the plant toanother.

[0004] Another example of a transport system is disclosed in documentU.S. Pat. No. 4,151,907 which shows a walking beam conveyor having a cam(32) at only one of its end driving a longitudinally extending beam(26). First and second linkage means (48, 54) move the beamtransversely, e.g. vertically, and longitudinally, e.g. horizontally, ofthe conveyor.

[0005] The prior art transport systems have a number of disadvantages,above all the low degree of precision in reaching accurate positionsalong the production line, which means that it is necessary to adoptoften expensive arrangements for ensuring the correct placement of thecontainers, for example, beneath the delivery nozzles of thedye-dispensing machines. It should be borne in mind that containers forpaints and varnishes often have a very small opening on the upper facewhich is closed with a cap once the container has been filled. The smalldimensions of that opening, together with the necessity to delivercorrectly often very small amounts of dye to the inside of thecontainer, make it necessary to provide means suitable for ensuring theexact centring of the hole below the delivery nozzle. Given the poorpositioning precision of the transport systems of known type, inconventional plants it is necessary to provide a series of additionalmeans at the individual work stations, such as guides, stops, mechanicalmanipulators, robots, and the like. This naturally involves acomplication of the plant both in mechanical terms and in control terms,with a consequent reduction in the reliability, repeatability andquality of production during the prolonged and intensive use for whichsuch plants are intended.

[0006] A further disadvantage of the known systems is the inability tomanage multi-form production, that is to say, in which the containershave different shapes and dimensions.

[0007] Another disadvantage of the transport systems of the prior art,especially for use in plants for the production of paints and varnishes,is the difficulty of keeping such systems clean, above all if a dyeproduct, a varnish or a paint is spilt or upset on them, which couldspoil the containers themselves and therefore impair the quality andappearance of the final packaging of the product.

[0008] The object of the present invention is to overcome thedisadvantages of the prior art by providing a system for transportingand handling containers which is precise and reliable and which is atthe same time economical and simple to produce.

[0009] In order to achieve that object, the present invention relates toa system for transporting containers, which is especially suitable foruse in a plant for the production of paints, varnishes and the like,characterised in that it comprises a longitudinally extending bearingstructure for containers, comprising a first, fixed, portion definingone or more fixed coplanar bearing surfaces, and a second, movable,portion defining one or more movable coplanar bearing surfaces, handlingmeans being connected operatively to the movable portion in order, inuse, to bring about coordinated movements of lifting/lowering andlongitudinal advance/return of the movable portion relative to the fixedportion.

[0010] A particular advantage of the present invention is afforded bythe fact that the handling system can be provided in modular form, withsegments of predetermined length which can be readily assembled to formportions of transporter of the desired length.

[0011] A further advantage of the present invention is provided by thefact that it is readily possible to clean the transport system owing tothe substantially planar form of the transport surfaces.

[0012] Another advantage of the present invention is that it is possibleto predetermine with precision not only the positioning of eachindividual container along the production line but also the relativedistance between one container and another, so as to ensure a correcttime sequence in the operation of the individual machines in each workstation without having to resort to the extensive and generalised use ofpresence-sensing means at each work station, which clearly hasfavourable results as regards the overall economy of the plant, itsreliability, and the simplicity of managing the complete productionprocess, especially with the large production volumes for which theplants of the type indicated above are intended.

[0013] Yet another advantage of the present invention is provided by thequiet operation of the transport system compared with the prior artsystems, owing to the fact that the impacts between the containers andthe bearing surfaces are substantially reduced and the risk of contactbetween the various containers, which remain spaced from one another bya predetermined distance over the entire handling path, are alsocompletely eliminated, thus also reducing the risk of the containersbeing damaged, in particular dented.

[0014] A further advantage of the present invention is provided by thefact that it is also possible to transport and handle simultaneouslycontainers having widely varying dimensions, without having to make anymodification to the structure or to the components of the transportsystem, and while still ensuring optimum precision of advance andpositioning along the path of the plant.

[0015] A further advantage resides in the fact that it is also possibleto produce long transport path segments operated by a single motor,simply by combining and connecting small modular portions which can bereadily stored and transported.

[0016] Naturally, although the invention has been developed withparticular regard to a plant for the production of paints, varnishes andthe like, the transport and handling system to which the inventionrelates could also be used in other technological fields which requirejust as accurate a system for positioning parts or members within theframework of a production line.

[0017] Further characteristics and advantages will emerge from thefollowing detailed description of a preferred embodiment, with referenceto the appended drawings which are given purely by way of non-limitingexample and in which:

[0018]FIG. 1 is a partially sectioned plan view of a modular portion ofthe transport system according to the present invention, comprising apower unit;

[0019]FIG. 2 is a sectioned side view taken on the line II-II in FIG. 1,

[0020]FIG. 3 is a cross-section taken on the line III-III in FIG. 2,

[0021]FIG. 4 is a plan view, similar to FIG. 1, of a modular portion ofthe transport system without a power unit;

[0022]FIG. 5 is a plan view, similar to FIG. 1, of a modular portionwith a power unit and a device for rotating the containers;

[0023]FIG. 6 is a sectioned side view taken on the line VI-VI in FIG. 5,and

[0024]FIG. 7 is a schematic perspective view of a group of containers atthe location of a device for rotating the containers.

[0025] Referring now to the drawings, a system for transportingcontainers along a production line comprises a succession of modularportions 10, 12, 14 of similar type which, as a whole, determine thepath along which a group of containers are transported in succession. Inparticular, the motor-driven modular portion 10, illustrated in FIGS. 1to 3, comprises a principal frame structure 16 including longitudinalsupport bars 18 resting on the ground by way of a plurality of legs 20having end feet 21 which are adjustable in height. Secured to theprincipal frame structure 16 are two longitudinal lateral shoulders 22which define two corresponding outer bearing surfaces 23. Also securedto the principal frame structure are two inner bearing girders 24 whichdefine two corresponding inner bearing surfaces 25 arrangedsymmetrically relative to the plane of the longitudinal centre line ofthe modular portion 10.

[0026] A handling beam 26 which is slidable both longitudinally andvertically relative to the principal frame structure 16 is arrangedalong the centre line of the modular portion 10. The beam 26 issupported by a plurality of lifting devices, for example, although thisis not to constitute a limitation, by the pneumatic jacks or cylinders28 illustrated in the drawings, which are secured firmly to the framestructure 16. A sliding system is interposed between the lifting devices28 and the beam 26 and is, for example, constituted by bearings 30 whichenable the beam 26 to slide longitudinally, irrespective of the verticalposition it assumes as a result of the cylinders 28 being operated. Atone of its ends the beam 26 is coupled to a motor 32, preferably anelectrical motor, with the interposition, in addition to an optionalreduction gear 33, of a connecting rod and crank mechanism 34 having aneccentric, or of any other type of mechanism normally known by a personskilled in the art which is suitable for transmitting the movement tothe beam 26 with conversion thereof from a rotary movement to a linearmovement.

[0027] Secured along the beam 26 are cross-members 36 on which aremounted intermediate bearing girders 38 which define two correspondingintermediate bearing surfaces 39 which are arranged symmetricallyrelative to the plane of the longitudinal centre line of the modularportion 10 and which are interposed with play between the lateralsurfaces 23 and the inner surfaces 25. The play between the surfaces 23and 25 is such as to ensure free relative movement between them but itis nevertheless sufficiently small to offer adequate protection againstaccident to the operators. A longitudinal support structure 40 is alsosecured to the beam 26 and defines a corresponding median bearingsurface 41 having a median duct 41 a for collecting any drops of productwhich might escape from the containers. The intermediate bearingsurfaces 39 and the median bearing surface 41 lie substantially in thesame horizontal plane which, when the beam 26 has been lowered to themaximum extent, is lower than the horizontal plane in which the lateralbearing surfaces 23 and the inner bearing surfaces 25 lie. The stroke ofthe lifting means 28 is such that, when the beam 26 has been raised tothe maximum extent, the horizontal plane in which the intermediatesurfaces 39 and the median surface 41 lie is raised above the horizontalplane in which the lateral bearing surfaces 23 and the inner bearingsurfaces 25 lie.

[0028] Referring now to FIG. 4, the simple modular portion 12, withoutany independent motorisation in the horizontal direction, but likewiseprovided with means 28 for lifting the central beam, comprises astructure substantially similar to that of the motor-driven modularportion 10, with the exclusion of the motor 32 and the handling devicesconnected thereto. Instead, the ends of the modular portion 12 areprovided with connecting means 42 which enable the modular portion 12 tobe connected to adjacent portions in order to derive from a remotemotor-driven modular portion 10 the movement of the central beam and ofthe structures connected thereto.

[0029] Referring to FIGS. 5 and 6, the motor-driven modular portion 14also comprises a device 44 for rotating the containers, which comprisesa pair of bearing tracks 46 supported by a platform 48 which isrotatable by means of a mechanism 50, which preferably, although thisdoes not constitute a limitation, includes a pneumatic linear actuatorand a bevel gear. Substantially, the tracks 46 lie on the extension ofthe girders 25.

[0030] The modular portions 10, 12, 14 described above can be coupledone behind the other. Preferably, a single motor-driven modular portion10 or 14 controls a plurality of simple modular portions 12 connectedthereto in succession. The lifting means 28 of the various modularportions are generally served by the same power supply, in particular bythe same source of compressed air, in order to bring about thesimultaneous lifting and lowering of all of the beams 26 of modularportions that are adjacent to one another, and therefore thesimultaneous lifting and lowering of all of the intermediate 39 andmedian 41 bearing surfaces relative to the parallel lateral 23 andintermediate 25 longitudinal bearing surfaces.

[0031] The lifting and lowering movement of the beams 26 is coordinatedby an external control system (not illustrated in the drawings) with thehorizontal sliding movement of the beams 26 and, consequently, of theintermediate 39 and median 41 longitudinal bearing surfaces.

[0032] When a series of containers is placed on the transport andhandling system formed by the series of modular portions 10, 12, 14connected adjacent to one another, in an initial stage the bases of thecontainers rest only on the lateral bearing surfaces 23 and/or on theinner bearing surfaces 25, depending on the transverse dimensions of thecontainers. The system for controlling the transporter then activatesthe lifting means 28, in particular, although this is not to constitutea limitation, by bringing about the delivery of compressed air to thepneumatic cylinders 28. The various beams 26 of the modular portions 10,12, 14 are raised in a manner such that the various intermediate 39and/or median 41 longitudinal bearing surfaces push simultaneously onthe bases of the various containers, lifting them and removing them fromthe lateral 23 and inner 25 bearing surfaces.

[0033] The control system then sends an activating signal to the motor32 which brings about the longitudinal advance of the beams 26. When thebeams have reached the longitudinally advanced position, the controlsystem brings about the deactivation of the lifting means 28 and theconsequent lowering of the various intermediate 39 and/or median 41longitudinal bearing surfaces. Thus, the series of containers is setdown gently again on the lateral 23 and/or inner 25 fixed supportsurfaces, but in a position advanced by a specific amount relative tothe starting situation.

[0034] When the movable bearing surfaces 39 and 41 have been lowered tosuch an extent that they no longer support the containers, the controlsystem activates the motor 32 so that it returns the beams 26 into thewithdrawn position, in order for the operating cycle to be resumed againfrom the beginning.

[0035] Although the operation of the transport system has been described above with reference to activation and deactivation commandsimparted by an external control system, it is nevertheless possible toprovide an operating procedure which does not require a complex controllogic. It is sufficient to synchronise a continuous alternating movementof lifting and lowering the beams 26, which is brought about by thelifting means 28, with a continuous longitudinal alternating movement ofthe beams 26 which is brought about, for example, by the connecting rodand crank mechanism connected to the motor 32. The result is a circularor elliptical movement in the vertical plane, in which the horizontalvelocity component of the guides 26 is zero at the front and rear deadcentres, which coincide with the moment at which all of the fixed 23, 25and movable 39, 41 bearing surfaces are aligned in a horizontal planecommon to the base plane of the various containers.

[0036] The rotation device 44, which can be either integrated in themodular portion 14 of FIGS. 5 and 6 or provided as a separate accessorywhich can be integrated in a transport system constituted by the modularportions 10 and 12, is advantageously used in cases where it isnecessary to rotate the containers at a work station, for example sothat they can be picked up by a manipulator before a set of mixers. Infact, in many cases it is necessary to orient the containers C, C′ in aspecific manner so that, for example, although this is not to constitutea limitation, the handles 50, 50′ are oriented in predefined directions.In such cases, when the movable surfaces 39, 41 are in the lowerposition of their movement, the tracks 46 can be rotated about avertical axis in order to present the containers C, C′ in the requiredposition for the subsequent production stages.

[0037] In the above description, the unit for operating the handlingmeans in the longitudinal direction of the transport system, comprisingthe motor 32, the optional reduction gear 33 and the mechanism 34 forconverting the movement from rotary to linear, has been described by wayof example as forming an integral part of the motor-driven modularportion 10. It will be appreciated that it is possible to provide asmentioned above with regard to the rotation device 44 an independentmotor-driven operating unit which can be integrated in a transportsystem comprising only simple modular portions 12. In that case, theplacing of such a motor-driven operating unit close to a simple modularportion 12 would basically assume a configuration analogous to that ofthe motor-driven modular portion 10 illustrated in FIG. 1, in which thebroken line J is intended to indicate the line of the plane joining themotor-driven operating unit (on the right in the Figure) and the simplemodular portion connected thereto (on the left in the Figure).

[0038] Naturally, the principle of the invention remaining the same, thedetails of construction and forms of embodiment may be varied widelywith respect to those described and illustrated, without therebydeparting from the scope of the invention.

1. A system for transporting containers, which is especially suitablefor use in a plant for the production of paints, varnishes and the like,comprising a principal structure (16) defining one or more bearingsurfaces (23, 25), a longitudinally extending bearing structure (26, 36,38, 40) for containers defining one or more movable bearing surfaces(39, 41), handling means being operatively connected to thelongitudinally extending bearing structure (26, 36, 38, 40) in order, inuse, to transport containers along a path, by longitudinally andvertically movements, characterised in that the handling means comprisesfirst operating means (28) in order to bring about movements oflifting/lowering of the movable bearing surfaces (39, 41) relative tothe principal bearing surfaces (23, 25), and second operating means (32,34) in order to bring about movements of longitudinal advance/return ofthe movable bearing surfaces (39, 41) relative to the principal bearingsurface-i (23, 25), the second operating means (28) being operableirrespectively of the vertical position assumed by the movable bearingsurfaces (23, 25).
 2. A transport system according to claim 1,characzerised in that the one or more principal (23, 25) and movablebearing surfaces (23, 25) are coplanar with one another.
 3. A transportsystem according to claim 1, characzerised in that the movement of themovable bearing surfaces (23, 25) relative to the principal bearingsurfaces (23, 25) is a generally circular or elliptical movement in avertical plane.
 4. A transport system according to claim 1,characterised in that it comprises at least two fixed and longitudinallyparallel bearing surfaces (23, 25) intercalated with at least twolongitudinally parallel movable bearing surfaces (39, 41).
 5. Atransport system according to claim 4, characterised in that theprincipal structure (16) comprises two lateral bearing surfaces (23) andtwo inner bearing surfaces (25), which are arranged symmetricallyrelative to the plane of the longitudinal centre line of the pathdefined by the transport system, the movable bearing surfaces comprisingtwo intermediate bearing surfaces (39), each being interposed withtransverse play between a lateral bearing surface (23) and an innerbearing surface (25), the movable bearing surfaces also comprising amedian bearing surface (41) arranged along the centre line of thetransport system and interposed with play between the two fixed innerbearing surfaces.
 6. A transport system according to claim 1,characterised in that it comprises modular portions (10, 12, 14) whichare arranged longitudinally side by side in succession and each of whichcomprises the bearing structure (26, 36, 38, 40) and the handling meansand which are selectively selected from the group comprising simplemodular portions, motor-driven modular portions comprising power meanscoupled to the handling means, and modular portions for rotation,comprising a device for the selective rotation of a container placed onthe bearing structure.
 7. A transport system according to any one of thepreceding claims, characterised in that the longitudinally extendingbearing structure comprises an elongate beam structure mounted on theprincipal portion (16) with the interposition of lifting means (28) andmounted to be slidable longitudinally relative to those lifting means(28).
 8. A transport system according to claim 7, characterised in thatthe beam structure is connected to means of longitudinal translation(32, 34) of the connecting rod and crank type.
 9. A transport systemaccording to claim 1, characterised in that the bearing structurecomprises a third portion mounted to be rotatable relative to the fixedportion in accordance with a vertical axis.
 10. A transport systemaccording to claim 1, characterised in that it comprises modularportions (10, 12, 14) which are arranged longitudinally side by side insuccession and each of which comprises the bearing structure and thehandling means, at least one of the modular portions being adjacent toand coupled to a motor-driven operating unit comprising power means andmeans of coupling to the handling means of the at least one adjacentmodular portion.